Nearly 80% of individuals with PD develop cognitive impairment and suffer increasing incidence of language dysfunction. These cognitive and language deficits in PD seriously compromise communicative effectiveness and quality of life, and limit the successful performance of many instrumental activities of daily living. Unfortunately, the current pharmacological and surgical interventions for PD fail to reliably improve cognition and may even create deleterious cognitive side effects. Language problems are usually overshadowed by the more prominent motor symptoms in PD and are rarely treated. As a result, no active treatments exist for improving either cognitive or language impairments in PD. To address these issues, the proposed exploratory study investigates the impact of aerobic exercise on cognitive and language performance in individuals with idiopathic PD. Because activities of daily life often require the ability to perform multiple tasks simultaneously, we will test the efficacy of aerobic exercise as an intervention for cognition and language in both single and dual task conditions. Our general hypothesis is that aerobic exercise potentiates neuroplasticity, particularly in the frontal lobes and, thus, will enhance behavioral measures of cognition and language production in the aerobic exercise group. Hypotheses will be tested under two specific aims: 1) Determine whether aerobic exercise improves cognitive performance in idiopathic PD, and 2) Determine whether aerobic exercise impacts language production in idiopathic PD. Forty-eight individuals with PD will be recruited and randomized into one of three groups: aerobic exercise, stretch intervention, or non-contact control. This innovative approach will allow us to control for learning and social contact effects in the PD group, determine whether the aerobic exercise intervention is efficacious for improving cognition and/or language deficits in PD, and compare the relative magnitude of the effects of aerobic exercise and a commonly-recommended stretch exercise program on cognition and language in PD. Furthermore, it will allow us to determine the robustness of the effects of aerobic exercise on cognition and language in PD by evaluating performance under single and dual task conditions. The findings from this exploratory project may substantially advance the development of treatments for PD, because they explore a drug-free intervention for cognitive and language impairment that can potentially have pervasive effects on patient well-being. PUBLIC HEALTH RELEVANCE: Parkinson's disease impairs not only motor function but cognitive and language abilities. This study evaluates the impact of aerobic exercise, relative to stretch exercise and no exercise, on cognitive performance and language production In Parkinson's disease using both single and dual task experimental paradigms.